Stevenjaguar and SkylerSquirrel: I hear you, but given that being in love with one person seems to make me blind to other potential lovers, I think I may need to go a little bit outside my comfort zone here, or else I could be waiting for years to find out if having multiple intimate/sexual relationships is a possibility for me. And by "outside my comfort zone," I mean something like creating a profile on OkCupid and intentionally starting to meet polyamorous guys, as opposed to just waiting to find someone by chance.
GalaGirl: Apologies for being unclear. I'm pretty new here. : ) You raised some excellent questions. To try to clarify a little, I'm not certain that I personally could thrive in the long term as a monogamous person with a polyamorous partner. In my mind, he would be enjoying all the benefits of polyamory while I have none of the benefits of monogamy and only some of the positives of polyamory, most of them related to his fulfillment and happiness, along with the negatives of polyamory, such time management issues. In my perception, this is inherently not an equitable arrangement, and it's hard for me to think how I could offset that imbalance.
SchrodingersCat: Thanks for the reassuring words. How to get my needs met in other ways, though, is a huge question mark for me. I suspect that taking up horseback riding or climbing Mount Everest is not going to do it - it's the intimacy my partner shares with others that makes our relationship feel lopsided to me.